This shrub is quite scarce in Rocky Mountain regional gardens, but Farrer knew it, mentioning it in My Rock Garden published in 1907.
I understand that there are a couple of other species in the genus Fendlera, linearis from west Texas and points southwest, and a few species in Mexico. Also F. wrightii which may just be a form of F. rupicola.
The common name is said to be “cliff bush”. Cliff bush. In some places, where the imagination is set free, and poetry reigns supreme, the plant becomes “cliff fendlerbush”.
Just in case there might be some confusion.